His heartbroken sister Margaret filmed him at his bedside when his breathing became irregular on August 8 last year.

The family have released the tragic footage in a bid to prompt any potential witnesses to come forward.

Shocking footage from the hospital bed was aired on BBC's Crimewatch tonight.

His sister said: "He started breathing irregularly. At the time I didn't know what was happening. I just saw something I hadn't seen before…the struggles to take breaths. So I started to film.

"I didn’t know that he was taking his last breaths."

MET POLICE

TRAGIC: Marvin Couson was gunned down in a Shoreditch bar

“I started to film. I didn’t know that he was taking his last breaths”

Margaret, Marvin Couson's sister

Det Ch Insp Noel McHugh, from the Homicide and Major Crime Command, said: "Marvin's shooting happened many years ago but you would remember if you were there that night and were one of those who fled in panic as shots were fired inside the bar.

"We need to speak to everyone who was there that night. I remain concerned some people may have a misguided sense of loyalty and are possibly protecting those who carried out this attack.

"Marvin should have celebrated his 40th birthday in November. Instead he spent 13 years in a hospital bed unable to do anything for himself before tragically succumbing to his injuries."

Police were called at 3:40am on Saturday, May 12, 2002 to reports of gunfire at the bar.

Cops found Marvin, then aged 26, on the ground outside the bar with a gunshot wound to the chest.

He suffered injuries to his heart and other internal organs and was left unable to care for himself or leave his hospital bed.

MET POLICE

HEARTBREAK: Marvin's sister Margaret filmed his last moments

He could not communicate and had no capacity to understand anything said to him.

Dad-of-two Marvin, who fitted security systems for retailers, had visited the Lime Bar with his cousin and a friend.

In the early hours they fled, along with a large number of other people, after shots were fired inside the bar.